Reversible bits for bulldozer and similar blades



June 22,1965 P. NELSON ETAL 3,190,018

REVERSIBLE BITS FOR BULLDOZER AND SIMILAR BLADES Filed Aug. 22, 1963 5 Sheets-Sheet 1 :5 I5 22 36 2 Q I? w I; Q L

37 .37 INVENTOR. 5' 6 EARL Rnznsmzn mmuw P. Nnsau Am's.

June 22, 1965 P. NELSON ETAL 3,190,013

REVERSIBLE BITS FOR BULLDOZER AND SIMILAR BLADES Filed Aug. 22, 1963 3 Sheets-Sheet 2 4= w nmaaqaw azaeameqlw!"" gmmxa I x\ so 28 30 29 30 40 He. 8 22 H6 9 ll 25 25 25 23 25 I6 .2 H46 H2 30 20 INVENTOR.

[ARL RITZHEIMER NACLAY P. NELSDN ATTYS.

June 22, 1965 M. P. NELSON ETAL 3,190,018

REVERSIBLE BITS FOR BULLDOZER AND SIMILAR BLADES Filed Aug. 22, 1 963 3 Sheets-Sheet a Z 1; mum

INVENTOR. EARL RITZHEIMER MACLAY R Nasal! ATrYs.

United States Patent Ofiice 3,l%,@l8 Patented June 22, I965 REVERSIBLE BITS FOR BULLDGZER AND SIMILAR BLADES Maclay P. Nelson, 6703 N. Washington, Spokane, Wash,

and Earl Ritzheimer, Bovill, Idaho (1704 Meadows Drive, Lake Oswego, Oreg.)

Filed Aug. 22, 1963, Set. No. 363,3tl7 6 Claims. (Cl. 37-443) 'type are merely bolted to the blade, and removal after the bolts have been battered by use and become rusted due to weather conditions is most difficult. The present invention contemplates a bit designed so as to be reversible, completely eliminating unprotected bolt surfaces so as to facilitate the replacement of the bit.

It is a first object of this invention to utilize a novel bit shape which allows the bit to be turned about and used twice in succession to protect the same blade surfaces. This reversible feature is incorporated across the full width of the blade, with the sole exception of the very central area.

Another object of this invention is to provide such a bit which is mounted on a blade by means entirely rear- 'ward of the cutting surfaces of the blade, so that the mounting means are at all times protected from damage due to impact against soil or rocks engaged by the bit or blade.

Another object of this invention is to provide a practical bit that can be mounted on a bulldozer blade by a single threaded nut, thereby minimizing the number of threaded members liable to damage during use.

These and further objects will be evident from a study of the following description, taken in conjunction with the accompanying drawings, which illustrate one preferred form of the invention. It is to be emphasized 'that this form of the invention is only by way of example,

and that various modifications might be incorporated in the device without deviating from the scope of the invention.

In the drawings:

FIGURE 1 is a perspective view of the front of the .tractor having mounted thereon a bulldozer blade of the type with which this invention is concerned;

FIGURE 2 is a front view of the blade or moldboard shown in FIGURE 1 with the instant bits mounted thereon;

FIGURE 3 is a rear view of the blade seen in FIGURE FIGURE 4 is an enlarged end view of the blade seen i in FIGURES 2 and 3;

FIGURE 5 is an enlarged vertical sectional view of the blade as seen along line 5-5 in FIGURE 3;

FIGURE 6 is an enlarged vertical section view of the blade as seen along line 6-6 in FIGURE 3;

FIGURE 7 is an enlarged view taken at one end of the blade as seen along line 7-7 in FIGURE 5;

FIGURE 8 is an enlarged rear view of a single bit;

FIGURE 9 is an end view of the bit as seen in FIG- URE 8;

FIGURE 10 is an enlarged front view of one corner of the blade as seen in FIGURE 2 with the bit removed;

FIGURE 11 is a rear view of a corner of a blade similar to FIGURE 10;

FIGURE 12 is an elevation view of the wedge used to lock an end bit in place; and

FIGURE 13 is a top view of the wedge seen in FIG- URE 12.

Referring now to the drawings, and particularly to FIGURES 1 through 7, there is shown a reversible corner bit assembly which is adaptable universally to bulldozer blades in order to protect the corner cutting edges thereof. There will also be described centrally located protective bits mounted similarly to the corner bits, but which could be modified in structure so as to be permanently mounted by bolts, since the center bits do not have to accommodate the wear encountered by the corner bits.

The moldboard or blade It is shown generally in FIG- URE 1 as it would be mounted on a tractor 11. The details of the mounting arrangement end of the tractor 11 are not described, since the mounting and tractor are entirely conventional and form no part of the present invention. Likewise the specific structure of the moldboard It) can be varied, depending upon the particular installation, and it is assumed that the bit assembly described below can be modified accordingly so as to be incorporated on any conventional moldboard 10.

The moldboard 10 has a front digging surface 12 and a rear surface 13. It is provided with a lower cutting edge I4 and end cutting edges 15 which may be either perpendicular to the lower edge 14 or which, as illustrated, may form an obtuse angle relative thereto.

Mounted along the lower edge 14 of the moldboard 10 and projecting slightly beyond and. parallel to the lower edge 14 and end edges 15 are a pair of end bits designated as 16, a pair of central bits designated as 17 and a V-shaped center bit 18. The manner by which these bitsare mounted upon the moldboard and the configuration given to the bits as and 17 form the basis of this invention.

Taking first the more universally required end bits 16, the bit 16 is formed with a lower edge 20 and an outer end edge 21. The lower edge 20 is parallel to the lower edge 14 of the moldboard It and the end edge 21 is parallel to the adjacent end edge 15 of the moldboard It). The bit 16 has an upper edge 22 parallel to the lower edge 20, and a second end edge 23 parallel to the end edge 21. Thus the end bit 16, as illustrated, has a parallelogram configuration. The parallelogram has end edges parallel to the end edges 15 of the moldboard 1d. The particular angle presented by the end edges 21 and 23 will 'be dependent upon the angle of the end edges 15 in a particular installation. Should the end edges 15 of the moldboard 10 be perpendicular to the lower edge 14, then the end bit It: will have a rectangular configuration.

Mounted along the rear surface of the end bit 16, which abuts the front surface 12 of the moldboard 10, are a plurality of projections 25 that extend rearwardly through corresponding slots or apertures 24 formed through the moldboard It). The projections 25, as well as edges 20 23, are located symmetrically through the intersection of perpendicular central axes located along the surfaces of the bit 16. Thus the bit 16 is identical when turned degrees. The projections 25 are provided with aligned apertures 26 which are rectangular in shape.

Mounted on the rear surface 13 of the moldboard It) between the slots 24 is a tapered surface 27 of increasing thickness toward the center of the moldboard It]. This tapered surface cooperates with a wedge 28, which is shown in detail in FIGURES 12 and 13, having a complernentary tapered surface 2? adapted to ride against the surface 27. The wedge 23 has a rear edge 43 adapted to ride against the rear surface 30 of the apertures 26. Thus as the wedge 28 is drawn longitudinally toward the center of the moldboards It it will push rearwardly :3) against the surfaces 3%), thereby drawing the bit 16 against the front surface 12 of the moldboard 10. The location of the rear surface 36 is such that when the end bit is is mounted on a moldboard lull, the'distance between the rear surface 13 of the moldboard 1i? and the rear surface 3% of the apertures 26 will be less than the maximum thickness of the tapered surface 26 plus the maximum thickness of the wedge 28. Thus the wedge 28 cannot be drawn beyond the extremities of the tapered surface 27.

The tapered surface 27 on the moldboard need not be continuous from aperture to aperture in the moldboard. In fact it is preferred that the ends of the tapered surfaces 27 between apertures 26 that are on one side of .It has been found that this imbalance of the wedging forces tends to urge the movable wedge more tightly in place to take up any wear.

In order to prevent accidental removal of the wedge 28 and also to facilitate the achievement of a tight wedging fit between the projections 25 and the surface 27, there is provided a threaded extension 31 at the inner end of the wedge 28 which projects through an aperture formed through one of the rigs 34 at the rear of the moldboard 10. The tapered surfaces 27 and wedge 23 likewise project through similar apertures cut through the ribs 34, as can be seen in FIGURE 7. The threaded extension 31 is secured by a nut 33 threadably engaged thereon, which bears against a washer 32 engaging the adjacent surface of the rib 34 as can be seen in FIG- URE 7.

As seen in FIGURE 2, the center bits 17 are also formed in the shape of a parallelogram, having parallel end edges 35 and parallel upper edges 36. The edges 35 are parallel to the end edges 21 and 23 of the end bit 16 adjacent thereto, and therefore are also parallel to the end edges 15 of the moldboard 10. The rear of each bit 17 is provided with symmetrical projections 37 in the same manner as described above. The projections 37 receive a wedge 48 that rests against a tapered surface 38 similar to that described above. The wedge 40 is capped by a threaded extension 44 engaged by a nut 42 and washer 41 which bear against an adjacent surface of a rib 34. The central bits 17 and the V-shaped center bit 18, which is provided with a single projection 37, are locked in place by a single wedge 40 in the illustrated embodiment. This wedge 40 can be replaced only when the right hand wedge 28, as seen in FIGURE 3, has been removed. The apertures in the ribs 34 must be sufiiciently large to admit the wedge 40' to the intended position it must assume in order to lock the two central bits 17 and the center bit 13 on the moldboard 10. This is easily accomplished, since the apertures in the ribs 34 are only for purposes of clearance, the wedging action of the wedges 28 or 4% being entirely between the tapered surfaces 27 or 38 and the projections 25 or 37.

The parallelogram shape and symmetry of the projections allow each of the bits 16 and 17 to be turned a full 180 degrees so that the four edges of each bit can be utilized as cutting surfaces in pairs. This doubles the life of each bit 16 or 17, and eliminates the necessity of packing additional bits into the field. The entire mounting apparatus is protected from scraping wear, since it is positioned rearwardly of the moldboard in a protected location. The threaded extensions 31 and 44 are protected from contact with soil or racks engaged by the moldboard 10 and will normally be undamaged so that the wedges 28 and 40 can be readily t removed when desired. There are no exposed mounting elements along the front surfaces of the bits 16, 17 and 13 vulnerable to damage during use of the bulldozer.

Various modifications could be made in the above apparatus without deviating from the scope of the invention. If desired, the central bit 17 and center bit 18 could be made of a unitary trapezoidal configuration, although this would not allow the reversal of the bit. Under many types of operations, the central portions of the blade do not encounter unusual wear, and need not be replaced at frequent intervals. The edges of the bit might not always be desired as parallel to the moldboard edges.

Since many equivalent types of devices could be used to fix the positions of the wedges 28 and 40 relative to the moldboard 10, and since many variations could be made in the particular mounting structure described, only the following claims are intended to limit or restrict the scope of the invention described herein.

Having thus described our invention, we claim.

1. A replaceable bit assembly for a moldboard comprising:

a moldboard having a row of parallel slots adjacent the lower edge thereof;

a bit fitted against the front surface of said moldboard and including rearwardly directed projections protruding through said slots, each projection being provided with an aperture aligned axially with one another parallel to the row of moldboard slots;

a longitudinal tapered surface on said moldboard facing rearwardly thereon, said tapered surface extending parallel to the row of moldboard slots;

and a wedge received through said apertures and bearing against said tapered surface adapted to prevent forward movement of said bit relative to said moldboard. 7

2. A bit assembly as defined in claim 1 wherein all edges of the bit are symmetrical through the intersection of perpendicular central axes located along the surfaces of the bit.

3. A bit assembly as defined in claim 1 wherein the bit has a parallelogram configuration.

4. A replaceable bit assembly for a moldboard comprising:

a moldboard having front and rear surfaces, and bottom and end edges;

an end bit abutting the front moldboard surface having a bottom edge and a first end edge positioned parallel to and projecting slightly beyond the adjacent bottom and edge edges of said moldboard, the upper edge and remaining end edge of said bit being respectively parallel to said bottom edge and said first end edge thereof;

a plurality of rearwardly directed projections on said bit through and beyond complementary apertures formed through said moldboard and projections being symmetrical about a pair of perpendicular central axes located on the bit surfaces; tapered rearwardly directed surface on said rear moldboard surface between said projections; complementary tapered wedge received through apertures formed through said projections and resting against said tapered surface and the rear surfaces of said apertures;

and locking means on said wedge and moldboard adapted to fix said wedge relative to said moldboard.

5. A replaceable bit assembly as defined in claim 4 wherein said tapered surface increases in thickness from the adjacent moldboard end edge toward the center of the moldboard, said locking means comprising:

a threaded extension at the end of said wedge of least thickness;

a rearward projection on said moldboard rear surface having an aperture through which is received the threaded extension;

and a threaded member threadably engaged on said threaded extension and bearing against the adjacent surface of said moldboard extension.

6. In combination with a moldboard having front and rear surfaces provided with a plurality of spaced slots formed therethrough in aligned parallel positions; a replaceable bit assembly comprising:

a metal plate adapted to about the front surface of the moldboard, at least, one edge of said plate corresponding in configurationlto an edge of the moldboard and adapted to be located adjacent thereto, said plate having a plurality of projections directed rearwardly therefrom, said projections being complementary to the moldboard slots in both cross section and location and adapted to be received therethrough;

a first longitudinally tapered member fixed to the rear moldboard surface intermediate said slots and in alignment therewith;

a second longitudinally tapered member formed complementary to said first member and of a length so as to span at least two of said projections, said projections having apertures formed therethrough in alignment with said first member and adapted to receive said second member, the rear surface of each aperture being spaced from said first member by a distance less than the maximum thickness of said second member;

and means on said moldboard and second member adapted to selectively restrict longitudinal movement of said second member relative to said moldboard.

References Cited by the Examiner UNITED STATES PATENTS 15 2,138,150 11/38 Flynnetal. 57-143 2,189,745 2/40 Johnson c 37143 ABRAHAM G. STONE, Primary Examiner.

20 WILLIAM A. SMITH III, Examiner. 

1. A REPLACEABLE BIT ASSEMBLY FOR A MOLDBOARD COMPRISING: A MOLDBOARD HAVING A ROW OF PARALLEL SLOTS ADJACENT THE LOWER EDGE THEREOF; A BIT FITTED AGAINST THE FRONT SURFACE OF SAID MOLDBOARD AND INCLUDING REARWARDLY DIRECTED PROJECTIONS PROTRUDING THROUGH SAID SLOTS, EACH PROJECTION BEING PROVIDED WITH AN APERTURE ALIGNED AXIALLY WITH ONE ANOTHER PARALLEL TO THE ROW OF MOLDBOARD SLOTS; A LONGITUDINAL TAPERED SURFACE ON SAID MOLDBOARD FACING REARWARDLY THEREON, SAID TAPERED SURFACE EXTENDING PARALLEL TO THE ROW OF MOLDBOARD SLOTS; AND A WEDGE RECEIVED THROUGH SAID APERTURES AND BEARING AGAINST SAID TAPERED SURFACE ADAPTED TO PREVENT FORWARD MOVEMENT OF SAID BIT RELATIVE TO SAID MOLDBOARD. 